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1
Sharma, Amrit Prasad. "Electronic characterization of swcnt/block copolymer-based nanofiber for biosensor applications." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2016. http://digitalcommons.auctr.edu/dissertations/3118.
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The aim of this research is to fabricate an electrically conducting, smooth, continuous and sensitive nanofiber using tri-block copolymer PS-b-PDMS-b-PS and SWCNTs by electrospinning. The electronic nanofibers may be utilized for effective biosensing applications. The SWCNTs have been of great interest to researchers because of their exceptional electrical, mechanical, and thermal properties. The nanoscale diameter, high aspect ratio, and low density make them an ideal reinforcing candidate for novel nanocomposite material. Electrically conducting fibers are prepared by electrospinning a solution of PS, PS-b- PDMS-b-PS and functionalized SWCNTs using solvent DMF. The fibers formed have an average diameter and height of 5 and 4 μm respectively. These fibers are characterized by SEM, AFM, and optical microscopy. The electrical characterization of a single fiber shows an almost linear graph of current vs. voltage using the Kelvin Sensing method. This linear graph exemplifies the conducting nature of the fiber. Future work includes preparing nanofibers decorated with functional groups and binding with specific type of enzyme or protein to study their I-V behavior. This approach or method can be utilized for bio-sensing activities, especially for the detection of various antibodies and protein molecules.
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Adams, Melanie Chantal. "Highly - conductive cathode for lithium-ion battery using M13 phage - SWCNT complex." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81137.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 27).
Lithium-ion batteries are commonly used in portable electronics, and the rapid growth of mobile technology calls for an improvement in battery capabilities. Reducing the particle size of electrode materials in synthesis is an important strategy for improving their rate capability and power density (which is the capacity at high rates). Using biological materials as a template during synthesis allows us to achieve this, improving synthesis methods. Utilizing biological materials makes it possible to synthesize nano-scale particles, and using the M13 virus has shown to be an early solution. The addition of conductive material, such as single-walled carbon nanotubes (SWCNT or CNT), also improves the conductivity of the electrode, further improving the battery's rate capabilities (Lee et al., 2009). In this study, our goal is to improve the conductivity of the LIB battery cathode using M13-carbon nanotube complexes.
by Melanie Chantal Adams.
S.B.
3
Müller, Christian, Ammar Al-Hamry, Olfa Kanoun, Mahfujur Rahaman, Dietrich R. T. Zahn, Elaine Yoshiko Matsubara, and José Mauricio Rosolen. "Humidity Sensing Behavior of Endohedral Li-Doped and Undoped SWCNT/SDBS Composite Films." MDPI AG, 2019. https://monarch.qucosa.de/id/qucosa%3A33173.
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We have investigated single-walled carbon nanotube (SWCNT) networks wrapped with the cationic surfactant sodium dodecyl-benzenesulfonate (SBDS) as promising candidates for water detection. This is the first time that the humidity behavior of endohedral Li-doped (Li@) and undoped SWCNTs/SDBS has been shown. We identified a strong and almost monotonic decrease in resistance as humidity increased from 11 to 97%. Sensitivities varied between −3 and 65% in the entire humidity range. Electrical characterization, Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) analysis revealed that a combination of the electron donor behavior of the water molecules with Poole-Frenkel conduction accounted for the resistive humidity response in the Li@SWCNT/SDBS and undoped SWCNT/SDBS networks. We found that Li@SWCNTs boosted the semiconducting character in mixtures of metallic/semiconducting SWCNT beams. Moreover, electrical characterization of the sensor suggested that endohedral Li doping produced SWCNT beams with high concentration of semiconducting tubes. We also investigated how frequency influenced film humidity sensing behavior and how this behavior of SWCNT/SDBS films depended on temperature from 20 to 80 ∘ C. The present results will certainly aid design and optimization of SWCNT films with different dopants for humidity or gas sensing in general.
4
Gupta, Ankit. "Multi-Scale Modeling of Mechanical Properties of Single Wall Carbon Nanotube (SWCNT) Networks." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1022.
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Single wall carbon nanotubes (SWCNTs) show a variety of unparalleled properties such as high electrical and thermal conductivity, high specific surface area (SSA) and a large stiffness under axial loads. One of the major challenges in tapping the vast potential of SWCNTs is to fabricate nanotube based macrostructures that retain the unique properties of nanotubes. Pristine SWCNT aerogels are highly porous, isotropic structures of nanotubes mediated via van der Waals (VDW) interactions at junctions. The mechanical behavior of such aerogels is examined in several experimental studies. However, it is necessary to supplement these studies with insights from simulations in order to develop a fundamental understanding of deformation behavior of SWCNT aerogels. In this study, the mechanical behavior of SWCNT networks is studied using a multi-scale modeling approach. The mechanics of an individual nanotube and interactions between few nanotubes are modeled using molecular dynamics (MD) simulations. The results from atomistic simulations are used to inform meso-scale and continuum scale finite element (FE) models. The deformation mechanism of pristine SWCNT networks under large compressive strain is deduced from insights offered by meso-scale simulations. It is found that the elasticity of such networks is governed by the bending deformation of nanotubes while the plastic deformation is governed by the VDW interactions between nanotubes. The stress response of the material in the elastic regime is dictated by the VDW stresses on nanotubes while in the plastic regime, both the VDW and axial deformation stresses on nanotubes drive the overall stress response. In this study, the elastic behavior of a random SWCNT network with any set of junction stiffness and network density is also investigated using FE simulations. It is found that the elastic deformation of such networks can be governed either by the deformation of the nanotubes (bending, axial compression) or deformation of the junctions. The junction stiffness and the network density determine the network deformation mode. The results of the FE study are also applicable to any stiff fiber network.
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Miller, Matthew Ryan. "Mechanical Properties of PLGA Polymer Composites Using Nonfunctionalized Carbon Nanotubes as Reinforcement." OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1203.
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Poly[lactic co-glycolic] acid (PLGA) is a biocompatible polymer commonly used in the field of tissue engineering, but its mechanical properties tend to be less than ideal for most orthopedic applications. Five PLGA composites, reinforced with 0 to 1% nonfunctionalized single-walled carbon nanotubes, were prepared and tested for tensile strength. In order to achieve consistent nanotube dispersions, sodium dodecyl sulfate was incorporated as a surfactant. The polymer scaffold fabrication methods were successful at creating suitable samples for tensile testing. After the tests were performed, scanning electron microscope images were taken to examine the fractured edges and determine the cause of failure. Analysis of fractured surfaces indicated good nanotube dispersions in all composite samples, and an increase in tensile strength, with respect to the control (0.532 MPa), was found for composites at the 0.07% nanotube and 0.09% nanotube concentrations (0.570 MPa and 0.643 MPa respectively). Total length at failure decreased as carbon nanotube concentration increased. This experiment showed a promising trend toward increasing the mechanical properties of PLGA/carbon nanotube composites and represented a prospective foundation for future research.
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Chan, Ka Keung. "SYNTHESIS AND FUNCTIONALITY STUDY OF NOVEL BIOMIMETIC N-GLYCAN POLYMERS." Cleveland State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=csu162309270958734.
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Mada, Mykanth Reddy Materials Science & Engineering Faculty of Science UNSW. "Fabrication and characterisation of SWCNT-PMMA and charcoal-PMMA composites with superior electrical conductivity and surface hardness properties." Awarded by:University of New South Wales. Materials Science & Engineering, 2009. http://handle.unsw.edu.au/1959.4/41831.
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Fabrication of SWCNT-PMMA and Activated Charcoal- PMMA composites was carried out by the compression moulding technique. Then Mechanical and Electrical properties of the composites were investigated. The morphological studies of composites showed a) good dispersion of fillers and b) good interaction between fillers and matrix. Electrical conductivity of SWCNT-PMMA composites was increased by 9 orders of magnitude (at 0.8 % volume fraction of SWCNT) and that of AC-PMMA composites increased by 16 orders of magnitude (at 17 % volume fraction of AC). The percolation threshold of both composites turned out to be lower compared to the theoretical values. A significant improvement in mechanical properties was obtained ??? particularly in AC-PMMA composites which showed a 400 % improvement in Vickers microhardness ??? raising the polymer matrix abrasion property literally to that of Aluminium alloys (Dobrazanski et al 2006). In conclusion, it is to be noted that Activated Charcoal - PMMA composites have a great potential for cost effective conducting polymer composite production by the use of cheap filler: In addition, the compression moulding technique shows good potential for cost effective fabricating technique for amorphous polymers with high electrical and mechanical properties.
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Porto, Arthur Barra. "Oxidação controlada e funcionalização de nanotubos de carbono de parede única: uma abordagem experimental e teórica." Universidade Federal de Juiz de Fora (UFJF), 2017. https://repositorio.ufjf.br/jspui/handle/ufjf/4817.
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O tratamento químico de nanotubos de carbono (NTC) é necessário para aprimorar suas propriedades, aplicações e remover impurezas. O tratamento, com ácidos fortes como H2SO4 e HNO3 tem sido a alternativa mais utilizada. A mistura desses ácidos fortes produz espécies eletrofílica NO2+, íon nitrônio, que é um potencial agente oxidante, cuja concentração depende da proporção da mistura H2SO4:HNO3. Neste trabalho, a interação entre o íon nitrônio e o nanotubo de carbono de camada única (SWCNT, do inglês Single-Walled Carbon Nanotube) foi explorado experimental e computacionalmente. Experimentalmente a solução H2SO4:HNO3 foi analisada em proporções diferentes (1:1, 2:1, 5:2, 3:1, 4:1, 5:1, 6:1, 7:1 e 8:1 v/v) e a concentração de íon nitrônio foi obtida utilizando-se uma curva analítica construída com uma solução padrão de NO2BF4 em H2SO4. Todas as espécies na mistura ácida foram caracterizadas por espectroscopia Raman. Os resultados mostraram que a concentração do íon nitrônio na mistura ácida varia de 0 até 4,53 mol/L. As misturas 2:1, 5:2 e 3:1 foram então utilizadas para a oxidação química de SWCNT por 4, 8 e 12 horas. As amostras finais foram analisadas por espectroscopia Raman, análise termogravimétrica (TG) e espectroscopia de raios X por dispersão de energia (EDS). Dentre os resultados, foram observados por meio da espectroscopia Raman uma alta desordem estrutural no sistema após a oxidação, com significativas mudanças nos modos de respiração radial (RBM), como o desaparecimento de bandas de tubos com pequenos diâmetros, além do aumento dada razão ID/IG de 0,027 para 0,59 em tubos oxidados com a mistura 3:1. As análises TG mostraram um aumento na temperatura de decomposição dos tubos em, pelo menos, 30ºC se comparado às amostras padrão, sugerindo um significativo grau de oxidação. Os resultados de EDS apontaram um aumento considerável na quantidade de oxigênio, passando de 7% para 20%, aumentando com o aumento do tempo de reação e com a concentração do íon nitrônio. Computacionalmente a interação entre o íon nitrônio e o SWCNT foi estudada através de cálculos de mecânica quântica. Foram analisados modelos do tipo armchair (5,5), sendo um tubo perfeito (P) e dois outros contendo defeitos do tipo Stone-Wales (SW) e monovacância (V1) para modelar regiões distintas na superfície do nanotubo. Para os modelos P e SW, o grupo funcional éter (COC) foi obtido como um produto principal, com um epóxido (CCO) encontrado como um intermediário de reação. As barreiras de energia livre de Gibbs foram de 31,7 kcal.mol-1 (P) e 37,8 kcal.mol-1 (SW) em solução aquosa à 298,15 K e 1 atm. O mecanismo envolvendo o modelo V leva à obtenção de uma carbonila (CO) como produto principal, formado espontaneamente através da adsorção do íon NO2+. O mecanismo de alta energia também foi descrito no modelo V, passando por um estado de transição, caracterizado como um anel do tipo oxaziridina. Através deste caminho um grupamento do tipo alcóxido (CO-) é formado inicialmente e reage com um carbono vizinho, produzindo um grupo funcional do tipo éter (COC). A energia livre de Gibbs de ativação foi de 4,5 e 11,2 kcal.mol-1 para primeiro (CO-) e segundo (COC) passos, respectivamente. Os resultados reportados sugerem o início da oxidação em meio ácido através da região de vacância, com primeira oxidação levando a uma carbonila, seguida das reações nos defeitos topológicos (P e SW) na superfície com a formação de um éter (COC) como principal produto.
The chemical treatment of carbon nanotubes (CNT) is necessary to improve their properties, applications and to remove impurities. Treatments with strong acids as H2SO4 and HNO3 is the mostly used alternative. The mixture of these strong acids produces the electrophilic species NO2+, the nitronium ion that is a potential oxidizing with concentration depending on the H2SO4:HNO3 proportion. In this work the interaction between the nitronium ion and a single-walled carbon nanotube (SWCNT) was explored experimentally e theoretically. Experimentally, the H2SO4:HNO3 solution was analyzed at different proportions (1:1, 2:1, 5:2, 3:1, 4:1, 5:1, 6:1, 7:1 and 8:1 v/v) and the nitronium ion concentration obtained using a calibration plot constructed from a standard solution of NO2BF4 in H2SO4. All the species in the acid mixture were characterized by Raman spectroscopy. The results showed that the concentration of nitronium ion in the acid mixtures varied from 0 to 4.53 mol/L. The mixtures 2:1, 5:2 and 3:1 were then used for the chemical oxidation of single-walled CNT for 4, 8 and 12 hours. The final samples were analyzed by Raman spectroscopy, thermal gravimetric analysis (TGA) and energy dispersive X-ray spectroscopy (EDS). It was observed by Raman spectroscopy a higher structural disorder in the system after the oxidation, with significant changes in RBM modes, such as disappearance of bands of small diameter tubes, and in the ID/IG ratio, which increases from 0.027 until 0.59 to CNT oxidized with 3:1 mixture. The TGA showed an increase in the temperature of the tube decomposition of at least 30ºC relative to the pristine form, suggesting a significant oxidation degree. The EDS data point to considerable increase of the oxygen amount from 7% to at least 20%, increasing with the reaction time and nitronium ion concentration. Theoretically the interaction between nitronium ion and SWCNT was studied by quantum mechanical calculations. In addition to the pristine (P) form of an armchair (5,5) SWCNT, two other species containing Stone-Wales (SW) and mono-vacancy (V1) defects were considered in order to model the distinct defective regions on the carbon nanotube surface. For the P and SW regions, the ether (COC) functional group was predicted as the main product, with an epoxide (CCO) found as a reactive intermediate. The Gibbs free energy barriers were predicted to be 31.7 (P) and 37.8 kcal mol-1 (SW) in aqueous solution at 298.15 K and 1 atm. The mechanism involving the V1 region leads to the carbonyl group (CO) as the main product, which is formed spontaneously upon NO2+ adsorption without energy barrier. A higher energy mechanism was also described for V1 region, passing through a transition state characterized as an oxaziridine-like ring. Through this pathway an alkoxy (CO-) is firstly formed and reacts with the neighbor carbon yielding the ether (COC) functional group. The activation Gibbs free energies were 4.5 and 11.2 kcal mol-1 for the first (CO- formation) and second (COC formation) steps, respectively. The results reported here suggest that at the beginning of oxidation in acid medium, the vacancy regions (V) are firstly oxidized leading to the carbonyl (CO) functional groups, followed by reactions at the topological defective parts (P and SW) of the tube surface where the ether (COC) function is the main product.
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Kraft, Thomas. "Ternary blend ink formulations for fabricating organic solar cells via inkjet printing." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0027.
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L’objectif final de la thèse est l'impression de la couche photo-active ternaire d'une cellule solaire organique en utilisant deux approches: l'une concerne l'apport de nanotubes de carbone (SWCNT) pour améliorer les propriétés de transport, l'autre concerne la préparation de mélanges ternaires de matériaux pour contrôler la couleur des cellules. Les encres pour la couche active incluant des SWCNT fonctionnalisés sont composées d’un donneur d'électron (polymère) (poly(3-hexylthiophène), [P3HT]) et d’un accepteur d'électron ( [6,6]-phényl C61-butyrique ester méthylique d'acide [PCBM]) et ont été développées pour la fabrication de cellules inversées. Ces cellules sont réalisées sur substrats de verre pour l'optimisation de leurs performances, puis sur substrats plastiques pour les applications. Diverses couches d'interfaces ont été testées, qui incluent l'oxyde de zinc (ZnO, couches obtenues par pulvérisation ionique (IBS) ou à partir de solutions de nanoparticules) pour la couche de transport d'électrons et le PEDOT:PSS, le P3MEET, le V2O5 et le MoO3 pour la couche de transport de trous. Des essais ont été effectués avec et sans CNT afin d’étudier leur impact sur les performances. Des résultats similaires sont obtenus dans les deux cas. Il était attendu que les CNT améliorent les performances, ce qui n’a pas été observé pour le moment. Des travaux supplémentaires sont donc nécessaires au niveau de la formulation de la couche active.Avec trois polymères de couleur rouge (P3HT), bleu (B1) et vert (G1), nous avons préparé des mélanges ternaires efficaces permettant l'obtention de couleurs jusque là indisponibles . Nous avons fait une étude sur le piégeage et les mécanismes de diodes parallèles associés aux mélanges. En général, nous avons constaté que les mélanges ternaires de polymères bleu et vert peuvent être décrits par une mécanisme de diodes parallèles, sans entrainer de perte de performances, ce qui n'est pas possible pour les systèmes P3HT:B1 :PCBM et P3HT:G1:PCBM qui se piègent mutuellement. L’objectif final du projet est l'impression de la couche photo-active ternaire d'une cellule solaire organique, composites ternaires (polymère:polymères:acceptor) ou dopés avec les SWCNT. Cette étape nécessite encore des développements futursTwo approaches were followed to achieve increased control over properties of the photo-active layer (PAL) in solution processed polymer solar cells. This was accomplished by either (1) the addition of functionalized single-walled carbon nanotubes (SWCNTs) to improve the charge transport properties of the device or (2) the realization of dual donor polymer ternary blends to achieve colour-tuned devices.In the first component of the study, P3HT:PC61BM blends were doped with SWCNTs with the ambition to improve the morphology and charge transport within the PAL. The SWCNTs were functionalized with alkyl chains to increase their dispersive properties in solution, increase their interaction with the P3HT polymer matrix, and to disrupt the metallic characteristic of the tubes, which ensures that the incorporated SWCNTs are primarily semi-conducting. P3HT:PCBM:CNT composite films were characterized and prepared for use as the photoactive layer within the inverted solar cell. The CNT doping acts to increase order within the active layer and improve the active layer’s charge transport properties (conductivity) as well as showed some promise to increase the stability of the device. The goal is that improved charge transport will allow high level PSC performance as the active layer thickness and area is increased, which is an important consideration for large-area inkjet printing. The use of ternary blends (two donor polymers with a fullerene acceptor) in bulk-heterojunction (BHJ) photovoltaic devices was investigated as a future means to colour-tune ink-jet printed PSCs. The study involved the blending of two of the three chosen donor polymers [red (P3HT), blue (B1), and green (G1)] with PC61BM. Through EQE measurements, it was shown that even devices with blends exhibiting poor efficiencies, caused by traps, both polymers contributed to the PV effect. However, traps were avoided to create a parallel-like BHJ when two polymers were chosen with suitable physical compatibility (harmonious solid state mixing), and appropriate HOMO-HOMO energy band alignment. The parallel diode model was used to describe the PV circuit of devices with the B1:G1:PC61BM ternary blend
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Yaya, Abu. "Interactions faibles dans les nanosystèmes carbones." Nantes, 2011. http://archive.bu.univ-nantes.fr/pollux/show.action?id=f1e38479-78b7-4d42-9bed-71420c161382.
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Avec le logiciel AIMPRO, qui fournit une modélisation quantique basée sur la théorie de fonctionnelle de densité, on étudie plusieurs exemples importants de la faiblesse des interactions intermoléculaires dans les nanomatériaux de carbone. Au niveau mécanique quantique, nos calculs donnent une compréhension fiable et améliorée du rôle et de la fonction des interactions intermoléculaires faibles, ce qui ne peut pas être prédit par des méthodes conventionnelles comme les potentiels interatomiques classiques. Premièrement, on étudie l’interaction entre le brome physisorbé sur les nanomatériaux de carbone (graphène, graphite, nanotubes de carbone simple [SWCNT] et double [DWCNT] parois). Pour le graphène, nous trouvons une nouvelle forme de Br2, à notre connaissance jamais présentée dans la littérature, où la molécule se trouve perpendiculaire à la feuille de graphène avec un dipôle fort. La bromation ouvre un gap de petite taille (86 meV) dans la structuré de bande électronique et dope fortement le graphène. Dans le graphite, Br2 reste parallèle aux couches de carbone avec un transfert de charge moins fort et sans dipôle moléculaire. À plus haute concentration, la formation de chaînes de polybromure est thermodynamiquement favorisée, mais n’a pas lieu spontanément à cause d’une barrière d’activation appréciable (27,01 kJ / mol). Avec les nanotubes monoparoi, le Br2 reste perpendiculaire à la surface du tube, comme observé avec le graphène; dans les fagots, le Br2 s'intercale comme dans le graphite. Les spectres Raman sont enregistrés afin de vérifier ce résultat. Dans la deuxième partie, on étudie des interactions d’empilement de type π-π entre le benzène d’une part, les chaînes oligomères de PPV d’autre part, avec des nanomatériaux de carbone. Pour le dimère du benzène, nous avons réussi à reproduire les structures stables trouvées par ailleurs via des calculs de plus haut niveau de théorie ; pour le benzène sur le graphène ou sur les SWCNTs, l'empilement est de type AB comme dans le graphite. L'orientation de l’interaction dans le cas PPV / PPV est différente de celle obtenue dans le cas PPV / nanotube ou PPV / graphène. Dans le premier cas des plans moléculaires sont orthogonaux, semblable à un empilement de PPV ou d'autres hydrocarbures aromatiques polycycliques. Dans les autres cas, l’axe de la chaîne de PPV se trouve parallèle au plan du graphène comme à l’axe des nanotubes, ce qui est attribué à des effets d'empilement π-π. L'analyse des fonctions d’onde près du niveau de Fermi suggère qu’il y a peu de couplage électronique entre PPV et SWCNTs. La différence d’interaction prévue entre PPV et nanotubes semi-conducteurs ou métalliques suggère une nouvelle conception de composites PPV-SWCNT pour les dispositifs électroluminescents organiquesThis thesis uses the ab initio density functional modeling programme AIMPRO to study several important examples of weak intermolecular interactions in carbon nanomaterials. At the quantum mechanical level, our calculations give a reliable and improved understanding of the role and feature of weak intermolecular interactions, which cannot be accurately predicted by conventional methods such as classical interatomic potentials. First, the geometry and binding of bromine physisorbed on carbon nanomaterials (graphene, graphite and single walled nanotubes) is studied. In graphene, we find a new Br2 form which is reported for the first time in this thesis, where the molecule sits perpendicular to the graphene sheet with an extremely strong molecular dipole. Bromination opens a small (86- meV) band gap and strongly dopes the graphene. In graphite Br2 is stable parallel to the carbon layers with less charge transfer and no molecular dipole. At higher Br2 concentrations polybromide chain structures are thermodynamically favoured, but will not occur spontaneously due to an appreciable formation barrier (27. 01 kJ/mol). For single walled nanotubes Br2 lies perpendicular to the tube surface similar to graphene, while in bundles Br2 intercalates similar to graphite. Experimental Raman spectra are recorded to verify this result. We next study π-π stacking interactions between benzene and PPV oligomer chains with various carbon nanomaterials. For the benzene dimer we successfully reproduce high level theory stable structures, and for benzene on graphene and SWCNTs, the stacking arrangement matches AB- stacking in graphite. The orientation of the interaction between PPV/PPV is different from PPV/nanotube or PPV/graphene. In the former the molecular planes are orthogonal, similar to the crystal packing in PPV, as well as in other polyaromatic hydrocarbons. In the others the PPV plane lies (axially) parallel to the substrates, attributed to π-π stacking effects. Wavefunction analysis suggests very little electronic coupling between the PPV and SWCNTs near to the Fermi level. Predicted differences in interaction between PPV and semi-conducting or metallic tubes suggest a new route to experimental ultraefficient composite PPV-SWCNT organic light emitting device design
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LUCCI, MASSIMILIANO. "Gas sensor based on single wall carbon nanotubes." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/601.
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Single-walled carbon nanotubes (SWNTs) are nowadays one of the most investigated materials and the realization of
ordered SWNT structures is of fundamental importance for the improvement of many technological fields, from the
non-linear optics to the realization of transistor, to the assembly of gas sensing devices.
A SWNT is formed by rolling a graphene sheet into a seamless cylinder with a diameter on the nanometer scale. The
individual SWNTs are joined each other and assembled into bundles by Van der Waals forces. Guest molecules can
potentially interact with SWNTs via the outer surfaces of bundles, the inside of the tubes and /or the interstitial channels
between the tubes in a bundle. These different situations are expected to play an important role in tuning the guest
molecule/SWNT interaction during gas adsorption and/or desorption, and have been investigated theoretically and
experimentally using different approaches.
In particular, the interaction between gaseous molecules and SWNTs has been investigated from different point of
view, including gas storage and gas detection through modification of electronic and thermal properties or through
modification of the field emission properties. Compared with conventional solid-state sensors, that typically operate at
temperatures over 200 °C, and conducting polymers-based sensors, that provide only limited sensitivity, sensing
devices assembled with single-wall nanotubes can exhibit high sensitivity and fast response time at room temperature.
Due to the high surface area of nanotubes, a little amount of nanotube material can provide many sites for gas
interaction. The accessibility of these sites depends on the status of aggregation of the nanotubes. Our preliminary
studies suggested that the sensitivity of a nanotube-based device can be optimized controlling the organization of the
SWNTs. Ordered bundles of SWNTs exhibit indeed a sensitivity double with respect to that of a disordered deposit.
This is likely due to the enhancement of surface area for organized SWNT systems with respect to randomly placed
SWNT bundles.
Hence, aligned nanotubes can serve as a very efficient material for use in gas detection. Directionality of SWNT can be
obtained directly during the synthesis process, or after manipulation of dispersed nanotubes, by mean of several
methods, such as filtration/deposition from suspension in strong magnetic fields, field emission, electrophoresis or
dielectrophoretical processes. In particular the use of electric fields to move, position and align SWNTs has been
reported in recent papers and the results indicate that both the electrophoresis (EP) and dielectrophoresis (DEP) routes
have potential advantages for arranging nanotubes in controlled systems.
Beyond the sensitivity, another severe constraint for gas detection is the time either for the reset of the sensor after
exposure to the gas, either for the acceleration of the response itself.
Since practical applications can be severely limited by slow absorption/desorption processes, we felt it worthwhile to
investigate in a systematic way some physical parameters affecting the sensor response.
In this thesis we present a study of NH3 ,NOx and H2 detection using organized SWNTs as sensing material and an
innovative procedure to improve the time response of the sensor by applying a back gate voltage. Moreover study
on gas detection and gas storage were done using QCM sensor.
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Schmucker, Wolfgang Josef [Verfasser], and Hans-Achim [Akademischer Betreuer] Wagenknecht. "Modulation der Wechselwirkungen und Untersuchungen zur Stabilität der DNA-SWCNT-Hybride mittels chromophor- und hydroxychinolinmodifizierter Oligonukleotide / Wolfgang Josef Schmucker. Betreuer: Hans-Achim Wagenknecht." Karlsruhe : KIT-Bibliothek, 2012. http://d-nb.info/1043779752/34.
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Mzoughi, Nada [Verfasser], Bernhard [Akademischer Betreuer] [Gutachter] Wolf, and Franz [Gutachter] Kreupl. "Inkjet-printed flexible and disposable biochips with SWCNT sensors for multiparametric microphysiological measurements / Nada Mzoughi ; Gutachter: Bernhard Wolf, Franz Kreupl ; Betreuer: Bernhard Wolf." München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1132248663/34.
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太田, 貴久. "ポリエチレングリコール修飾によるペプチド被覆カーボンナノチューブの分散安定化と得られた複合体のドラッグデリバリーシステムキャリアへの応用に関する研究." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215491.
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Ibrahim, Imad. "Fabrication of high yield horizontally aligned single wall carbon nanotubes for molecular electronics." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-117433.
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The extraordinary properties of the single wall carbon nanotubes (SWCNTs) have stimulated an enormous amount of research towards the realization of SWCNT-based products for different applications ranging form nanocomposites to nanoelectronics. Their high charge mobility, exceedingly good current-carrying capacities and ability to be either semiconducting or metallic render them ideal building blocks for nanoelectronics. For nanoelectronic applications, either individual or parallel aligned SWCNTs are advantageous. Moreover, closely packed arrays of parallel SWCNTs are required in order to sustain the relatively large currents found in high frequency devices. Two key areas still require further development before the realization of large-scale nanoelectronics. They are the reproducible control of the nanotubes spatial position/orientation and chiral management. In terms of nanotube orientation, different techniques have been demonstrated for the fabrication of horizontally aligned SWCNTs with either post synthesis routes (e.g. dielectrophoresis and Langmuir-Blodgett approach) or direct growth (e.g. chemical vapor deposition (CVD)). The low temperature of the production process, allowing the formation of aligned nanotubes on pretty much any substrate, is the main advantage of the post synthesis routes, while the poor levels of reproducibility and spatial control, and the limited quality of the aligned tubes due to the inherently required process steps are limitations. The simplicity, up-scalability, along with the reproducible growth of clean high quality SWCNTs with well-controlled spatial, orientation and length, make CVD the most promising for producing dense horizontally well-aligned SWCNTs. These CVD techniques suffer some drawbacks, namely, that because they are synthesized using catalyst particles (metals or non-metals) the catalyst material can contaminate the tubes and affect their intrinsic properties. Thus, the catalyst-free synthesis of aligned SWNT is very desirable. This thesis comprises detailed and systematic experimental investigations in to the fabrication of horizontally aligned SWCNTs using both post growth (Dielectrophoresis) and direct growth (CVD) methods. Both catalyst-assisted and catalyst-free SWCNTs are synthesized by CVD. While metallic nanoparticles nucleate and grow SWCNTs, opened and activated fullerene structures are used for all carbon catalyst-free growth of single wall and double wall carbon nanotubes. The systematic studies allow for a detailed understanding of the growth mechanisms of catalyst and catalyst-free grown SWCNTs to be elucidated. The data significantly advances our understanding of horizontally aligned carbon nanotubes by both post synthesis alignment as well as directly as-synthesized routes. Indeed, the knowledge enables such tubes to be grown in high yield and with a high degree of special control. It is shown, for the first time, how one can grow horizontally aligned carbon nanotubes in crossbar configurations in a single step and with bespoke crossing angles. In addition, the transport properties of the aligned tubes at room temperature are also investigated through the fabrication of devices based on these tubesDie außergewöhnlichen Eigenschaften von einwandigen Kohlenstoffnanoröhren (engl. single wall carbon nanotubes, SWCNTs) haben bemerkenswerte Forschungsaktivitäten zur Verwirklichung von auf SWCNTs basierenden Anwendungen für verschiedene Bereiche, die von Nanokompositen bis hin zur Nanoelektronik reichen, stimuliert. Ihre hohe Ladungsträgermobilität und die außerordentlichen hohen Ladungsdichten, die in SWCNTs erreicht werden können sowie ihre Eigenschaft, entweder halbleitend oder metallisch zu sein, machen sie zu idealen Konstituenten von nanoelektronischen Schaltkreisen. Für Anwendungen in der Nanoelektronik sind entweder einzelne oder parallel angeordnete SWCNTs vorteilhaft. Darüber hinaus sind dicht gepackte Anordnungen von SWCNTs erforderlich, um die relativ hohen Ströme in Hochfrequenzbauelementen zu transportieren. Für eine erfolgreiche Realisierung von großskaligen nanoelektronischen Bauteilen, die auf SWCNTs basieren, sind noch zwei enorm wichtige Kernprobleme zu lösen, die weitere Forschungsanstrengungen erfordern: die reproduzierbare und verlässliche Kontrolle der räumlichen Positionierung und Orientierung der Nanoröhren sowie die Kontrolle der Chiralität der einzelnen SWCNTs. Hinsichtlich der Orientierung der Nanoröhren kann die horizontal parallele Ausrichtung von SWCNTs mit verschiedenen Techniken erreicht werden. Diese setzen entweder nach dem eigentlichen Wachstum der Röhren ein (Post-Synthese-Methoden wie z.B. Dielektrophorese oder Langmuir-Blodgett-Techniken) oder erreichen direkt während des Wachstums (z.B. durch Chemical-Vapor-Deposition-Methoden (CVD)) die parallele Anordnung. Durch die niedrigen Prozesstemperaturen, die während des Herstellungsprozesses erforderlich sind, erlauben die nach der eigentlichen Synthese stattfindenden Ausrichtungsmethoden die parallele Anordnung von Nanoröhren auf nahezu jedem Substrat, jedoch stellen die geringe Reproduzierbarkeit dieser Prozesse, die schwierige Kontrollierbarkeit der räumlichen Anordnung und die limitierte Qualität der ausgerichteten Röhren aufgrund der erforderlichen Prozessschritte natürliche Beschränkungen dieser Techniken dar. Die einfache Durchführung und ihre Skalierbarkeit, zusammen mit dem reproduzierbaren Wachstum qualitativ sehr hochwertiger SWCNTs mit hoher Kontrolle von räumlicher Anordnung, Orientierung und Länge machen die CVD-Methode zur erfolgversprechendsten Technik für die Herstellung von dichtgepackten hochparallelen horizontalen Anordnungen von SWCNTs. Diese CVD-Ansätze weisen jedoch auch einige Nachteile auf, die in den bei der Synthese verwendeten Katalysatorpartikeln (metallisch oder nicht-metallisch) begründet liegen, da das Katalysatormaterial die Röhren kontaminieren und dadurch ihre intrinsischen Eigenschaften beeinflussen kann. Daher ist eine katalysatorfreie Synthesemethode für ausgerichtete SWCNTs ein höchst erstrebenswertes Ziel. Die vorliegende Arbeit beschreibt detaillierte und systematische experimentelle Untersuchungen zur Herstellung von horizontalen, parallel ausgerichteten Anordnungen von SWCNTs unter Verwendung von Methoden, die sowohl nach dem eigentlichen Wachstum der Nanoröhren (Dielektrophorese) als auch während des Wachstums ansetzen (CVD). Bei den CVD-Methoden werden sowohl solche, die auf der Verwendung von Katalysatoren basieren, als auch katalysatorfreie Techniken verwendet. Während metallische Nanopartikel den Ausgangspunkt für das Wachstum von SWCNTs darstellen, werden geöffnete und aktivierte Fullerenstrukturen verwendet, um das katalysatorfreie Wachstum von reinen ein- oder mehrwandigen Nanoröhren zu erreichen. Die systematischen Untersuchungen ermöglichen ein tiefgehendes Verständnis der Wachstumsmechanismen von SWCNTs, die unter Verwendung von Katalysatoren oder katalysatorfrei erzeugt synthetisiert wurden. Die erzielten Ergebnisse erhöhen in einem hohen Maß das Verständnis der Herstellung von horizontal parallel angeordneten Nanoröhren, die durch Post-Synthese-Methoden oder direkt während des Wachstumsprozesses ausgerichtet wurden. Die erzielten Einsichten erlauben die Herstellung solcher Strukturen mit hoher Ausbeute und mit einem hohen Maß an räumlicher Kontrolle der Anordnung. Zum ersten Male kann ein Verfahren präsentiert werden, mit dem horizontal parallel angeordnete Nanoröhren in gekreuzten Strukturen mit wohldefinierten Kreuzungswinkeln hergestellt werden können. Zusätzlich werden die Transporteigenschaften von parallel ausgerichteten Nanoröhren bei Raumtemperatur, durch die Herstellung von auf den dargestellten Strukturen basierenden Bauelementen, untersucht
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Shahverdi, Ali. "In situ purification in large-scale production of single-walled carbon nanotubes by induction thermal plasma." Mémoire, Université de Sherbrooke, 2008. http://savoirs.usherbrooke.ca/handle/11143/1540.
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Single-walled carbon nanotubes (SWCNTs) are new forms of carbon nanostructure that have exhibited important physical and chemical properties with a wide range of future applications including microelectronic devices, nanoscale transistors, catalyst supports, biosensors, reinforcement materials, medical chemistry, etc. Up to now, many versatile methods have been used for SWNCT synthesis. These methods can produce SWCNT besides many by-products such as amorphous carbon, fullerenes, nanocrystalline graphite and multi-walled carbon nanotubes. For the exploration of the physical properties of SWNCT and to investigate the possibilities of chemical functionalization it is advantageous to work with a material that is as pure as possible. The work presented here is focused on in situ purification of SWCNT soot synthesized by a large-scale (i.e., production rate of ~100 g h[superscript -1]) induction thermal plasma process. The main objectives of this research are: 1) to get rid of amorphous carbon impurities from SWCNT soot produced in the induction thermal plasma system, 2) to study the effect of oxidizing gas flow rate (i.e. oxygen) and temperature on the purification process. The methodology used in this experimental design is based on gas-phase thermal oxidation of synthesized SWCNT soot. The experimental apparatus can be divided in to two parts as follows: 1) synthesis system which consists of a flow type reactor equipped with a high frequency plasma torch operated at 3 MHz along with quenching and filtration systems 2) purification system which consists of an oven and a gas heater used to control the temperature of oxidizing gases, and a filtration system where thermal oxidation of the synthesized soot takes place. SWCNT soot was synthesized by an induction thermal plasma process using a mixture of carbon black (Raven 860 ultra) as a carbon source and nickel (Ni), cobalt (Co) and yttrium oxide (Y[subscript 2]O[subscript 3]) as catalysts. A series of preliminary experimental tests was conducted to evaluate the process ability to purify SWCNT soot in situ using a gas-phase thermal oxidation process. In these tests, temperature measurements along the filtration system were carried out during synthesis and purification processes. Two types of oxidizing gases (i.e., air and oxygen) were injected into the filtration system and the purified samples were characterized by different powerful techniques such as high resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), thermo-gravimetric analysis (TGA) and Raman spectroscopy. The results indicated that in situ removal of amorphous carbon from SWCNT soot synthesized by induction thermal plasma can be successfully achieved (a purity of more than 60 wt% of SWCNTs was achieved). Moreover thermal oxidation of the soot causes a narrower distribution of tube diameters in the purified sample. Overall, the findings of this study are relevant to the purification process technology of SWCNTs and future research is proposed to fully understand the reaction mechanism of SWCNT soot by oxygen. Based in the results of this work, additional work using a modification of the filtration system (i.e., collection chamber and filter tubes) should be performed in order to get rid of other carbonaceous impurities. Different gases can be also introduced in to the filtration system to improved the purification process and extend it for removal of catalysts particles. Our findings reveal that the present synthesis system has a capability for functionalization of tubes in situ. Therefore according to the type of functional groups which are desired to be attached to the tubes, proper gases can be injected into the filtration system.
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Oftadeh, M., M. Gholamian, and H. H. Abdallah. "Investigation of Interaction Hydrogen Sulfide with (5,0) and (5,5) Single-Wall Carbon Nanotubes by DFT Method." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35161.
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In the present study the interaction of Hydrogen Sulfide with inside and outside single-wall carbon
nanotube of (5,0) and (5,5) was investigated. This study was conducted using DFT at B3LYP/6-31G* level
of theory. Computational calculations were performed in the gaseous phase in Gaussian 09. The geometry
of all molecules under investigation was determined by optimizing all geometrical variables without any
symmetry constraints. The harmonic frequencies were computed from analytical derivatives for all species
in order to define the minimum-energy structures. The adsorption energies, the thermodynamic properties,
HOMO-LUMO energy gaps and partial charges of the interacting atoms were also studied during two rotation
kinds of H2S molecules vertical and horizontal to the main axes of nanotube.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35161
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Dutta, Debosruti. "Insights into the Epitaxial Relationships between One-Dimensional Nanomaterials and Metal Catalyst Surfaces Using Density Functional Theory Calculations." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5213.
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This dissertation involves the study of epitaxial behavior of one-dimensional nanomaterials like single-walled carbon nanotubes and Indium Arsenide nanowires grown on metallic catalyst surfaces. It has been previously observed in our novel microplasma based CVD growth of SWCNTs on Ni-Fe bimetallic nanoparticles that changes in the metal catalyst composition was accompanied by variations in the average metal-metal bond lengths of the nanoparticle and that in turn, affected nanotube chirality distributions. In this dissertation, we have developed a very simplistic model of the metal catalyst in order to explain the nanotube growth of specific nanotube chiralities on various Ni-Fe catalyst surfaces. The metal catalyst model is a two-dimensional flat surface with varying metal-metal bond lengths and comprising of constituent metal atoms. The effect of the composition change was modeled as a change in the bond length of the model catalyst surface and density functional theory based calculations were used to study specific nanotube caps. Our results indicated that nanotube caps like (8,4) and (6,5) show enhanced binding with increased metal-metal bond lengths in the nanoparticle in excellent agreement with the experimental observations. Later, we used this epitaxial nucleation model and combined with a previously proposed chirality-dependent growth rate model to explore better catalysts that will preferentially grow an enhanced chirality distribution of metallic nanotubes. From our DFT calculations and other geometrical considerations for nanotube growth, we demonstrated that the pure Ni0.5Cu0.5 metal nanoparticles and its lattice-strained surfaces can serve as a promising catalyst for enhanced growth of metallic nanotubes. Finally, we extended this model of epitaxial growth to study the growth of,andoriented nanowires on gold metal nanoparticles where a faster growth rate ofnanowires was previously observed in experiments on shaped nanoparticles than that on spherical nanoparticles. The DFT calculations indicated an enhanced growth selectivity of theoriented nanowires on the Au(111) surfaces. However, the DFT results also show that theandNWs will preferentially grow on the Au(100) surface than on the Au(100) surface. The epitaxial model based DFT calculations of nanotube and nanowire growth on metal catalyst surfaces presented in this dissertation, provide a deep insight into their epitaxial growth mechansims and, can be easily exploited to layout better design principles of synthesizing catalysts that helps in growing these one-dimensional nanomaterials with desired material properties.
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RIGONI, FEDERICA. "EXPLORING DETECTION LIMITS AND RESPONSE TIME SCALES OF CHEMIRESISTOR GAS SENSORS BASED ON CARBON NANOTUBE AND HYBRID LAYERS." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/262413.
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Crucial features in gas sensors for environmental monitoring are the gas sensitivity in the low ppb range and the ability to discriminate variations of a certain polluting gas from other interfering gases.
Monitoring of ammonia gas concentrations is mandatory to reduce the hazard for human health and vegetation determined by the widespread use of ammonia derivatives as agricultural nitrogen fertilizers, industrial production and traffic. In particular, ammonia, besides being a toxic molecule is one of the main precursors of secondary fine particulate matter (PM10, PM2.5). Ammonia could hence be used as a local marker of secondary fine particulate formation, allowing indirect control of particulate emission sources. In spite of this urgency, the detection of NH3 concentrations in urban areas with chemiresistor gas sensors (CGSs) has been so far widely overlooked, since the average levels are usually low, i.e. in the 20-30 ppb range, while the CGSs are generally tested by exposure to ammonia in the ppm range.
Carbon nanotubes (CNTs), discovered more than 20 years ago, are well known and studied systems for many applications, among which (of course) gas sensing. With respect to commercial electrochemical sensors (mostly based on metal oxide materials), CNTs show a higher physical and chemical stability, better transport of charge to the electrodes and a wide range of possible hybrid architectures and operational features, among which the operation at room temperature, that make them unique materials for gas detection.
The main goal of this thesis is to increase the sensitivity to [NH3] and to lower the detection limit (DL), exploring sample preparation strategies of low-cost single walled carbon nanotubes (SWCNT)-based gas sensors operating at room temperature, considering also the response to other interfering gases. Furthermore, effects of metal oxide nanoparticles functionalization and gas response of hybrid layers have been also investigated.
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Schmidt, Andreas. "Carbon nanostructures for femtosecond mode-locked lasers in the 1.0 to 2.1 micrometer wavelength range." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2016. http://dx.doi.org/10.18452/17552.
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Die vorliegende Dissertation behandelt das Zusammenspiel von effizienten aktiven Lasermedien und neuartigen sättigbaren Absorbern, welche auf den Kohlenstoff-Nanostrukturen Graphen und den einwandigen Kohlenstoff Nanoröhren (SWCNTs) basieren. Die aktiven Lasermedien decken den Spektralbereich von 1,0 Mikrometer bis 2,1 Mikrometer ab, d.h. eine ganze Oktave, und nutzen die laseraktiven Ionen des Ytterbiums, Chroms und Thuliums. In dieser Arbeit werden die auf Graphen und SWCNT basierenden sättigbaren Absorber hinsichtlich ihres einer Anregung folgenden Relaxationsverhaltens, ihrer von der Fluenz abhängigen Transmission und ihres Sättigungs- verhaltens bei hohen Fluenzen untersucht. Eine vorangestellte Einführung der optischen Eigenschaften von Graphen und SWCNTs wird gegeben und die Modelle zur Beschreibung realer Proben werden aus theoretischen Modellvorstellungen hergeleitet. Die sättigbaren Absorber basierend auf Graphen und SWCNTs werden untereinander und mit klassischen halbleitenden sättigbaren Absorbern verglichen. Diese Arbeit zeigt ferner die Erzeugung ultrakurzer Pulse verschiedener Laser mit diesen neuartigen sättigbaren Absorbern basierend auf Kohlenstoff Nanostrukturen. Die erhaltenen Pulse werden mittels Spektrometrie, Autokorrelation, Radiofrequenz- und partiell FROG-Messungen charakterisiert, und der zugrunde liegende Pulsformungsmechanismus, sowie die Stabilität gegen das Güteschalten werden diskutiert.This thesis addresses the interplay of highly efficient active laser media and novel saturable absorbers based on the carbon nanostructures graphene and single-walled carbon nanotubes (SWCNTs). The active laser media cover the spectral region from 1.0 micron up to 2.1 micron, i.e. a whole octave, and apply ytterbium, chromium and thulium as active lasing ions. Within this work, the saturable absorbers based on SWCNTs and graphene are characterized with respect to their relaxation behaviour after excitation, and with respect to their fluence-dependent transmission and saturation. A precedent introduction of the general optical properties of graphene and SWCNTs is presented as well and the models to describe real samples experimentally are deduced from theoretical model conceptions. The saturable absorbers based on graphene and SWCNTs are compared to each other and to classical semiconducting saturable absorbers. This thesis further presents the generation of ultrashort laser pulses applying these novel carbon nanostructure based saturable absorbers in different lasers. The obtained pulses are characterized by spectrometry, autocorrelation, radio-frequency measurements and partially by FROG measurements. Additionally, the underlying pulse formation process and the Q-switching stability are discussed.
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Grimm, Daniel. "A combined experimental and theoretical approach towards the understanding of transport in one-dimensional molecular nanostructures." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1218037048209-51309.
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This thesis comprises detailed experimental and theoretical investigations of the transport properties of one-dimensional nanostructures. Most of the work is dedicated to the exploration of the fascinating effects occurring in single wall carbon nanotubes (SWCNT). These particular nanostructures gained an overwhelming interest in the past two decades due to its outstanding electronic and mechanical features. We have investigated the properties of a novel family of carbon nanostructures, named here as Y-shaped rings. The studies show that they present very interesting quantum interference effects. A high structural stability under tensile strain and elevated temperatures is observed. Within the semi-classical potential adopted, the critical strain values of structure rupture lie in the same range of their pristine SWCNT counterparts. This is directly verified by the first observations of these ring-like structures in a transmission electron microscopy. A merging process of asymmetric into symmetric rings is investigated in-situ under electron beam irradiation at high temperatures. The electronic properties of these systems are theoretically studied using Monte Carlo simulations and environment dependent tight-binding calculations. From our results, we address the possibility of double-slit like interference processes of counter-propagating electron waves in the ring-like structures. The nature of well defined, sharp peaks in the density of states are determined as the discrete eigenenergies of the central loop part. Furthermore, the formation and dispersion of standing waves inside the ring is shown to originate from the quantum-dot like confinement of each branch between the leads. The obtained dispersion relation is shown to be the same occurring in purely one-dimensional quantum dots of similar geometries. Furthermore, Fabry-Perot-like interferences are observed. We established at the IFW a bottom-up processing route to fabricate nanotube based electronic devices. The SWCNTs are grown by chemical vapor deposition and we present a detailed study of the different approaches to obtain individual nanotubes suitable for a successful integration into electronic devices. Wet-chemistry and ultra-thin films as well as ferritin were employed as catalyst particles in the growth of SWCNT samples. By adjusting the optimized process parameters, we can control the obtained yield from thick nanotube forests down to just a couple of free-standing individual SWCNTs. The nanotubes are localized, contacted by standard e-beam lithography and characterized at ambient- as well as liquid helium temperatures. We usually obtain quite transparent contacts and the devices exhibit metallic or a mixed metallic/semiconducting behavior. The well-known memory effect upon gate voltage sweeping as well as single electron tunneling in the Coulomb blockade regime are addressed.
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Castan, Alice. "Growth and Characterization of Single-walled Carbon Nanotubes from Chemically Synthesized Catalyst Precursors." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS028/document.
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Les propriétés des nanotubes de carbone monoparois (SWCNTs) dépendent fortement de leur structure atomique. La croissance sélective en structure des SWCNTs est donc un objectif clé à atteindre pour les applications potentielles de ces matériaux uniques. Dans le travail présenté dans ce manuscrit, nous proposons une nouvelle méthode originale alliant chimie de coordination et chimie des surfaces, pour la croissance de SWCNTs par décomposition chimique en phase vapeur, à partir de pré curseurs de catalyseurs variés synthétisés par voie chimique.L 'étude approfondie de ce procédé est présenté pour trois systèmes métalliques de précurseurs (Fe, NiFe, NiCr), issus de la famille du bleu de Prusse. Une caractérisation détaillée des précurseurs, catalyseurs, et des SWCNTs synthétisés a permis de mettre en évidence des effets de la composition du catalyseur sur les phénomènes de croissance.Une étude comparative de microscopie électronique en transmission et de spectroscopie Raman pour la détermination de la distribution de diamètre des échantillons de SWCNTs obtenus a été effectuée, mettant en lumière l 'importance primordiale du recours à des caractérisations croisées pour l 'évaluation de la sélectivité des croissances.Enfin, d'autres pistes de précurseurs de catalyseurs synthétisés par voie chimique sont explorées. Des résultats préliminaires sur deux systèmes bimétalliques de précurseurs issus de la famille des « cyanosols » (FePd) , et de celle des polyoxometallates (CoW) sont présentés, soulignant leur intérêt pour la compréhension des mécanismes complexes de croissance des SWCNTsThe work presented in this manuscript is focused on the study of single-walled carbon nanotube (S WCNT) growth by chemical vapor deposition, through the tuning of catalyst nanoparticle composition. The properties of S WCNTs strongly depend on their atomic structure, making structurally selective growth essential for future applications. Here we present a new and original method combining surface chemistry and coordination chemistry, for S CNT growth using a wide range of mono- and bimetallic catalyst systems, formed by the reduction of chemically synthesized catalyst precursors.A thorough study of this process is presented for three metallic precursor systems (Fe, NiFe, NiC), derived from the Prussian blue compound family. An extensive characterization of the precursors, ca -talysts, and the resulting S CNTs has allowed to evidence effects of catalyst composition on growth phenomena.We also show the importance of cross-characterization of SWCNT growth samples, through a comparative study between TEM, and Raman spectroscopy for diameter distribution assessment of our growth samples, and on diameter-sorted SWCNT samples.Preliminary results on the use of cyanosols and polyoxomet alates for SWCNT growth with additional bimetallic catalyst systems (FePd , and CoW) are also presented , highlighting the rich potential of inorganic chemistry and coordination chemistry in the field of SWCNT growth
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Chung, Chia-Ling. "Study of DNA- SWNT conjugation for nanoelectronic purposes : realisation of transistors and SWNT positioning in DNA T scaffold." Paris 11, 2010. http://www.theses.fr/2010PA112033.
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Dans cette thèse l’ADN a été envisagé comme un matériau de choix pour l’auto-assemblage de circuits à base de SWNTS. Afin de réaliser cette vision ambitieuse, plusieurs étapes sont nécessaires et dans cette thèse nous nous intéressons à trois d’entre elles : l’assemblage de l’ADN sur nanotubes. Nous avons exploré deux approches : l’approche covalente (chapitre 2) et l’approche non covalente ( chapitre 3). Les résultats obtenus nous ont servi à évaluer quelle méthode était la plus pertinente pour la fabrication de transistors. La conclusion de ces études a été que l’approche non covalente basée sur le système biotin-streptavidine est plus appropriée pour la fabrication de SWNT-FET en raison de son rendement plus élevé. (II) La fabrication d’une nanostructure d’ADN en forme de T, l’idée était ici de créer un échafaudage d’ADN imitant la géométrie d’un transistor a grille individuel. Nos résultats démontrent qu’il est possible de définir le design d’une structure d’ADN pour une fonction donnée et de le positionner sélectivement et spécifiquement un nanotube sur cette structure a trois branches. (III) Finalement nous décrivons la fabrication de dispositifs à base de nanotubes et d’ADN (chapitre 5). Nous avons réalisé des transistors par assemblage biorigide en utilisant les étapes suivantes : A) formation d’un complexe ADN-nanotubes, B) Métallisation sélective de l’ADN, C) fabrication des électrodes sur l’ADN métallisé par lithographie électronique et D) mesure des caractéristiques I/V. Les résultats démontrent la faisabilité des dispositifs, les transistors obtenus présentent un comportement de type P classique pour les nanotubes de carboneIn this thesis DNA has been envisioned as a scaffold for self assembly of SWNTS circuits on a substrate to realise this ambitious vision, several steps are needed and we address three of them in this thesis : I) DNA SWNT conjugation experiments. We test two approaches: covalent Approach (chapter2) and non –convalent approach (chapter 3). In order to evaluate which approach is suitable to fabricate DNA assembled SWNT-FET. Our results reveal that non-convalent approach by biotin-streptavidin system is the more appropriate for our DNA-based SWNT-FET fabrication, because of its superior linkage yield. (II) The assembly of a T-Shape DNA scaffold. In chapiter 4, we present a three branched DNA scaffold which can be the template of a SWNT field effect transistor. We design an artificial three branched DNA structure that mimics the geometry of an individual gated transistor. Our results demonstrate that it is possible to design sub-micrometric branched DNA structures for a given function, and directly an specifically localize one SWNT onto a three armed functionalized DNA template. (III) Finally, the fabrication of bio-directed SWNT-FET (chapter 5) through the following steps : (A) formation of DNA SWNT complexes using biotin-streptavidin system, (B) selective DNA metallization, (C) fabrication of electrode contacts on the metallized DNA strand by lithography and (D) the conductivity measurement the results reveal, the feasibility of the approach ant that our bio-directed SWNT-FET presents the typical P type SWNT-FET
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Steinert, Brian W. "Electroconductive PET/SWNT films by solution casting." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2009r/steinert.pdf.
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Brewer, Ashley. "Supramolecular porphyrin arrays on DNA and SWNT scaffolds." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/202885/.
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A variety of supramolecular porphyrin arrays on DNA or single walled carbon nanotube scaffolds are presented herein. A novel porphyrin modified nucleoside with multiple degrees of freedom about the linking moiety has been synthesised. Oligonucleotide strands containing the novel ‘flexible’ porphyrin modified nucleoside or a previously published ‘rigid’ linked porphyrin modified nucleoside were synthesised. The resulting systems were analysed by photospectrometric techniques. Stable B form duplexes were observed in all cases, with the porphyrin modifications imparting a stabilising effect on the duplexes, the degree of stabilisation the novel porphryin monomer provides is of a similar level to that of the rigid linked monomer. Excitonic coupling of the porphyrins is observed; the different monomers incorporated into DNA show different effects in the circular dichroism spectra, which may be explained through the increased conformational freedom of the ‘flexible’ linker. The synthesis of a novel anthraquinone modified nucleoside is presented. Modified DNA strands containing both porphyrin modifications and anthraquinone modifications were synthesised and analysed electrochemically. Cyclic voltammetry has shown that the inclusion of multiple porphyrin modifications increase the electron transfer rate to the anthraquinone redox marker. The synthesese of a novel ferrocenyl modified nucleotide, a novel naphthalene diimide modified nucleotide and an alternative synthesis route for a ruthenium tris-bipyridyl nucleoside are presented. Homo- and hetero-porphyrin single walled carbon nanotube adducts have been prepared with neutral, tetra-anionic and tetra-cationic porphyrins. Significantly elevated loading levels have been observed for the mixed charge species which forms a 1:1 salt on the nanotube surfaces
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Chang, Tae-Eun. "Microscopic mechanism of reinforcement and conductivity in polymer nanocomposite materials." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1176746415.
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Daine, Robert John. "Temperature Dependence of Current Transport in Metal-SWNT Structures." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1438958818.
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MILETIC, TANJA. "FUNCTIONAL CHROMOPHORES FOR LIGHT-HARVESTING APPLICATIONS." Doctoral thesis, Università degli Studi di Trieste, 2016. http://hdl.handle.net/11368/2908014.
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This doctoral thesis describes the design, synthesis and characterization as well as investigations of the optical properties of new functional chromophores. In the recent years, the term “functional dyes” used in a wild range of application areas, such as dyes for liquid crystals, lasers, displays, solar cells or bioimaging emphasize on the new functionality beyond color of π-conjugated chromophores.[1] In Chapter I a briefly insight into the general aspects of functional chromophores and emitters for light-harvesting, along with a concise outline of the manuscript is given to the reader. The preparation and physical characterization of oligo(p-phenylene vinylene)-derived single-walled carbon nanotubes (SWCNTs) conjugates are described in Chapter II. Moreover, further testing of functionalized SWCNTs as doping agents for spiro-OMeTAD in a flat CH3NH3PbI3-based solar cell was presented. Chapter III describes the synthesis of a novel class of O-doped polyaromatic hydrocarbons, in which two polyaromatic hydrocarbon substructures are bridged through one or two O atoms. This includes high-yielding ring-closure key steps that, depending on the reaction conditions, allow the formation of either furanyl or pyranyl structure through intramolecular C-O bond formation, and the stepwise planarization of oligonaphthalenes. X-ray single-crystal diffraction showed that the furanyl derivatives undergo π-π stacking at the solid state. Photophysical measurements showed very nicely that the molecules feature high emission yield and tunable absorption UV-Vis properties. Finally, Chapter IV reports the preparation of a distinct category of π-conjugates, more in detail; a new family of bis-perylenol derivatives bearing different dihedral angles between the two perylene moieties was prepared and studied in terms of UV-Vis and emission spectroscopy.
[1] a) Chen, Z.; Lohr, A.; Saha-Möller, C. R.; Würthner, F. Chem. Soc. Rev.2009, 38, 564–584. b) Weil, T.; Vosch, T.; Hofkens, J.; Peneva, K.; Müllen, K. Angew. Chemie - Int. Ed.2010, 49, 9068–9093
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Wang, Tong. "Light Scattering Study on Single Wall Carbon Nanotube (SWNT) Dispersions." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5200.
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Carbon nanotubes, and particularly single wall carbon nanotubes (SWNTs) have attracted much attention for their unique structure, as well as for their excellent mechanical, electrical and thermal properties. Most properties of carbon nanotubs are closely related with its anisotropic structure and geometry factor. Characterization of carbon nanotube length is critical for understanding their behavior in solutions as well as in polymer composites. Microscopy, particularly atomic force microscopy, has been used for their length measurement. Microscopy, though straightforward, is quite laborious, particularly for statistically meaningful sampling.
Light scattering can be used to measure particle dimensions. In this study, light scattering has been used to study polyvinyl pyrrolidone (PVP) wrapped SWNTs surfactant assisted aqueous dispersion and SWNT dispersion in oleum. To determine the length of SWNTs, Stokes - Mueller formalism was used, which is a universal model for particles with any size and shape. The Mueller matrix for an ensemble of long, thin cylinders proposed by McClain et al. was used in this study. This Mueller matrix includes the information of size (length and radius) and optical constants (refractive index and extinction coefficient) of cylinders. In this matrix, extinction coefficient, radius and length of SWNTs are unknown. By normalizing scattering intensity I(theta) (theta from 30 to 155 degree) to that at 30degree , the effects of radius and extinction coefficient were cancelled out. Thus, the effect of SWNT length on scattering intensity could be studied independently. A series of curves of normalized scattering intensity of SWNTs (I(theta) /I(30degree)) with varied length as a function of wave vector were predicted. A curve of normalized scattering intensity of SWNT as a function of wave vector was also obtained experimentally. By comparing experimental and predicted curves, average SWNT length in the dispersion has been determined.
Scattering intensity at a given angle initially increases with concentration, and then reaches a critical concentration(C*), above which the scattering intensity decreases. This phenomenon has been attributed to the competition between scattering and absorption of light by the presence of SWNT. By using Beer-Lambert law, this phenomenon has been used to determine the molar absorption coefficient of SWNTs.
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Hornbostel, Björn [Verfasser]. "Laserunterstützte Synthese von einwandigen Kohlenstoffnanoröhren (SWCNTs) und Applikationen in Polycarbonaten / Björn Hornbostel." Heimsheim : Jost-Jetter, 2008. http://d-nb.info/997172568/34.
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Lentaris, Georgios. "In-situ growth of SWCNTs and ZnO nanowires for transistors in nanotechnology." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610704.
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Gabriel, Buguña Gemma. "Purificació i estudi de la funcionalització de nanotubs de carboni (SWNT)." Doctoral thesis, Universitat Autònoma de Barcelona, 2005. http://hdl.handle.net/10803/3188.
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Una primera part del treball es va basar en la purificació dels SWNTs impurs de partida (de l'empresa CarboLex). La caracterització d'aquest material per ATG va permetre determinar un contingut d'òxids metàl·lics (Ni/Y) d'un 40.7 % en pes; la relació d'àrees integrades del mode tangencial dels nanotubs i de formes desordenades de carboni de l'espectre Raman és d'11.6. Imatges de TEM permeten veure com els nanotubs coexisteixen de manera altament heterogènia amb formes desordenades de carboni i metalls. La distribució de diàmetres calculada tenint en compte les interaccions de Van der Waals és d'1.40 - 1.63 nm.Es va realitzar una primera purificació per tractament amb àcid. Les millors condicions experimentals trobades són 24 hores de reflux amb una concentració 1.00 mgNT/ml d'HNO3 2.6 M. La millor mostra té una puresa del 96.6 % en pes respecte els metalls i una relació d'àrees de 5.8 de proporció de nanotubs respecte formes desordenades de carboni.
Es van realitzar tractaments tèrmics en oxigen a 300ºC posteriors al tractament àcid. Aquests van resultar sempre efectius en l'eliminació de formes desordenades de carboni, obtenint com a millor mostra una relació d'àrees de 21.4. No totes les mostres obtingudes tenien una relació d'àrees superior a la de la mostra impura, en canvi totes han augmentat el seu grau de puresa respecte a les corresponents tractades àcidament.
Finalment es va realitzar un procés de recuit, en el buit a 1000 ºC amb diferents temps de reacció. No es va aconseguir realitzar un procés de recuit amb èxit, ja que en tots els casos la quantitat de formes desordenades de carboni presents a la mostra va resultar ser superior a la corresponent mostra no tractada.
Una segona part es va basar en l'estudi de la funcionalització dels nanotubs de carboni per tal de purificar-los i solubilitzar-los. Es van assajar diferents vies de funcionalització amb amines aromàtiques (2-aminoantracè (aan)), alifàtiques (Octadecilamina (oda)) i fluorades (4-perfluorooctilanilina (pfa), 2,4-bis(perfluorooctil)anilina (pf2a) i la 1-H,1-H,-pentadecafluorooctilamina (foa)), basades en SWNTs producte de reaccions de formació del clorur d'àcid (Via 1 i via 3) o de tractaments àcids (Via 3 i via 4). La caracterització dels materials funcionalitzats obtinguts amb aminoantracè per les tres vies anomenades demostra que aquestes són finalment equivalents. Depenent de la basicitat d'aquestes amines, anàlisis d'XPS van permetre determinar:
- Els SWNTs-oda tenen aquesta molècula quimioadsorbida en la superfície dels SWNTs. L'XPS dóna que l'energia d'enllaç del N1s de l'amina és de 399.4 eV, la qual coincideix amb el valor corresponent a una amida patró (399.2 eV).
- En els SWNTs-amines polifluorades les amines no s'enllacen químicament als nanotubs sinó que estan fisiadsorbides o atrapades per interaccions febles a l'estructura d'aquests. L'XPS dóna que l'Eb N1s = 400.2 eV es correspon a l'Eb del N1s de l'amina patró (400.1 eV).
- Els SWNTs-aan tenen part de l'amina quimioadsorbida sobre els nanotubs i part que no s'enllaça químicament. L'XPS mostra un pic que es pot resoldre amb dues gaussianes amb energies d'enllaç properes a 399 eV i 400 eV, les quals es poden assignar a la presència de l'aan enllaçat químicament via enllaç amida i aminoantracè no enllaçat. L'espectre d'emissió de les dissolucions de SWNT-aan presenten dues bandes (738.5 nm i 465 nm), les qual indiquen la formació de dues espècies químiques noves, i entre elles diferents, que emeten a longituds d'ona diferent de l'aan (483 nm en THF).
La funcionalització dels nanotubs s'ha revelat com un bon mètode de solubilitzar o dispersar aquests materials en diferents dissolvents.
The first part of this work was done in the purification of SWNTs purchased at CarboLex. Material characterization by TGA enabled us to determine that there was 40.7 weight % of metal oxide (Ni/Y); integrated area ratio of carbon nanotubes tangential mode and disordered carbon in Raman spectrum was 11.6. In TEM images can be marked out nanotubes, metals and disordered carbon. Calculated diameter distribution (taking care of Van der Waals interactions in ropes) is 1.40-1.63 nm.
The first purification treatment was an acid treatment. Results confirm metal elimination, and the optimal conditions found were reflux with nitric acid 2.6 M, 24 hours with a concentration 1.00 mgNT/ml d'HNO3. The best sample had 3.4 weight % of metal oxide and an area ratio of 5.8.
Thermal treatments in oxygen and 300ºC were realized after the acid one. These ones removed disordered carbon, obtaining area ratio of purified nanotubes in the order of 21.4. Moreover, there were samples that do not reach the purity of raw material.
Finally, we performed an annealing treatment at 1000ºC and vacuum at different reaction times. Unfortunately we could not make it successful because the quantity of disordered carbon was higher than the thermal purified ones.
The second part of this work was based on carbon nanotubes functionalization for their purification and solubilization. Different synthesis routes were assayed: aromatic amines (2-aminoanthracene (aan)), aliphatic (Octadecilamine (oda)) and fluorated amines (4-perfluorooctilaniline (pfa), 2,4-bis(perfluorooctil)aniline (pf2a) and 1-H,1-H,-pentadecafluorooctilamine (foa)). These reactions were based on the formation of acyl chloride (way 1 and 3) or acid treatment (Way 3 and 4). Characterization of carbon nanotubes functionalized with aan allowed us to confirm that all the routes were equivalent. Depending on the amines basicity, XPS analysis allowed us to see that:
- SWNTs-oda: oda molecule is chemisorbed in SWNTs surface. XPS analyses show that this amine has a binding energy of N1s 399.4 eV. This one corresponds to the value of the measured standard (amide) 399.2 eV.
- SWNT-perfluorated amines: molecules are not covalent attached to nanotubes, they are physisorbed or trapped into ropes by weak interactions. XPS analyses show that this amine has a binding energy of N1s 400.2 eV. This one corresponds to the value of the measured standard (amine) 400.1 eV. This can be explained due to the low basicity of the fluorated amines.
- SWNT-aan: this amine is partially chemisorbed and partially physisorbed. XPS analyses show one band which is formed by two Gaussian peaks with binding energies near 399 eV and 400 eV. Each one corresponds to the aan covalent attached to nanotubes and to aan adsorbed to the surface. Emission spectrum of soluble SWNT-aan shows two peaks (738.5 nm and 465 nm) different from the free aan (438 nm in THF). These ones can be understood as two different and new species formed.
We can state that nanotubes functionalization is a good way for the solubilization or dispersion of these materials in different solvents.
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Uzunpinar, Cihan Auad Maria Lujan. "Effect of dispersion of SWCNTs on the viscoelastic and final properties of epoxy based nanocomposites." Auburn, Ala., 2010. http://hdl.handle.net/10415/2043.
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Chen, Yi-chieh. "Raman spectroscopic studies on single-walled carbon nanotubes (SWNTs) and SWNT/Ag nanostructure." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492122.
Full textAbstract:
Raman spectroscopic studies on individual single-walled carbon nanotubes (SWNTs) were conducted by analysing the Radial Breathing Modes (RBMs) and other Raman bands of SWNTs prepared both from separating commercial SWNTs and from a chemical vapour deposition (CVD) process. Tentative chirality assignments of the CVD grown SWNTs were made by combining the findings from the RBM spectra and the G- or G'-band spectra obtained using various laser energies, and the diameter distributions of the samples were determined. In addition, polarised Raman studies were performed on the CVD grown SWNTs, and samples containing aligned SWNTs were also investigated to determine the degree of the alignment and to correlate with FE-SEM image analysis of the samples. SWNT networks decorated with Ag nanoparticles using electrochemical deposition were characterised using various laser wavelengths to probe the surface-enhanced Raman scattering (SERS) effect of this nanostructure. The Raman intensity enhancements of the SWNTs were found to be dependent on the density and size of the Ag particles, and the dependence of the enhancement varied with the laser energies used. The findings were further correlated with the localised surface plasmon resonance (LSPR) of the Ag nanoparticles, showing that the stimulation of the LSPR using various lasers wavelength is responsible for the different Raman intensity enhancement of the SWNTs. The SWNT/Ag nanostructure was also used as a SERS substrate for the detection of pyridine absorbed on the substrate. The results demonstrate the possibility of using this nanostructure for generic SERS sensing purposes.
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Kao, Chih-chuan. "Study of the deformation of single-walled carbon nanotube(SWNT)/epoxy composites using Raman spectroscopy." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556555.
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Lamberti, Francesco. "ELECTROCHEMICAL SENSORS BASED ON SINGLE-WALLED CARBON NANOTUBES FOR BIOLOGICAL DETECTION." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3423226.
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In this work thesis we aim at discussing electrochemical biosensors based on single-walled carbon nanotubes for biological detection. The main strategy is to obtain modified electrodes with carbon nanotubes with two different classes of strategy. This can be realized in two ways: a surface modification strat- egy and a bulk modification strategy. The first one concerns the modification of patterned gold electrodes in which the tridimensionality is assured by the creation of a controlled forest of single-walled carbon nanotubes. The second strategy proposed is the modification of electrodes by means of a bulk doping of materials. We realized carbon nanotubes doped polyacrylamide hydrogels (HYs) acting as biosensors for glucose detection.
Finally examples for the integration of biosensing and microfluidic environ- ments are proposed. Electrochemical measurements (EIS, CV and CA) were performed in order to characterize samples and substrates. Also morphological measurements (AFM and SEM) were conducted to study topographic features of samples. Biocom- patibility tests and electrical measurements were performed when treating with living systems.In questo lavoro di tesi vogliamo discutere biosensori elettrochimici modificati con nanotubi di carbonio a parete singola. La strategia principale è di ottenere elettrodi modificati con nanotubi di carbonio attraverso due classi diverse di modificazione. Ciò può essere realizzato in due modi: attraverso una modifica della superficie dell’elettrodo oppure attraverso una modifica della struttura del materiale. Per quanto riguarda la prima si tratta di una modificazione di elettrodi d’oro disegnati in cui la tridimensionalità è assicurata dalla creazione di una forest controllata di nanotubi di carbonio a parete singola. La seconda strategia proposta è la modifica di elettrodi per mezzo di doping di materiali. Si sono realizzati hydrogel (HYs) di poliacrilammide drogati con nanotubi di carbonio a parete singola in modo da funzionare come biosensori per il rilevamento di glucosio. Infine vengono proposti esempi per l’integrazione dei biosensori in piattaforme mifcrofluidiche. La caratterizzazione dei substrati e dei campioni è stata condotta per mezzo di misure elettrochimiche (EIS, CV e CA). Vengono eseguite inoltre misure di caratterizzazione morfologica (AFM e SEM) per studiare le proprietà topografiche dei campioni in esame. Nei casi in cui si è avuto a che fare di sistemi viventi sono state condotte prove di biocompatibilità e prove per il riconoscimento del segnale elettrico dalla superficie delle cellule.
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Prudkovskiy, Vladimir. "Electronic properties of quasi-one-dimensional systems (C60@SWCNTs and InAs nanowires) studied by electronic transport under high magnetic field." Thesis, Toulouse, INSA, 2013. http://www.theses.fr/2013ISAT0013/document.
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Cette thèse présente des mesures de transport électronique dans des systèmes quasi-unidimensionnels (quasi-1D) sous champ magnétique intense. Deux systèmes différents présentant un confinement électrique quasi-1D ont été considérés: les peapods de carbone (C60@SWCNTs) et les nanofils d'InAs. L’objectif de ces travaux consiste à sonder les propriétés électroniques spécifiques de ces systèmes quasi-1D par les mesures de magnétotransport sur les nano-objets uniques. Dans les deux cas, les expériences sous champs magnétiques intenses ont été accompagnée par des caractérisations structurales et des mesures de conductance à champ magnétique nul.L'encapsulation de diverses molécules à l'intérieur de nanotubes de carbone (CNTs), comme par exemple les fullerènes C60, constitue une des voies prometteuses vers l'accordabilité de la conductance des CNTs. Parmi la grande variété des nanotubes de carbone remplis, les peapods représentent une structure hybride pionnière découvert en 1998. Depuis lors, leur structure électronique a fait l’objet d’études théoriques controversées avec un nombre limité de réalisations expérimentales. Dans cette thèse, les propriétés électroniques des peapods individuels ont été étudiés en combinant les mesures de spectroscopie micro-Raman et de magnétotransport sur les mêmes échantillons. Nous avons constaté que les C60 encapsulés modifient fortement la structure de bande électronique des nanotubes semi-conducteurs au voisinage du point de neutralité de charge. Cette modification comprend un déplacement rigide de la structure électronique et un remplissage partiel de la bande interdite. Nous avons aussi montré que l’excitation UV sélective des fullerènes conduit à une forte modification du couplage électronique entre les C60 et le CNT induite par la coalescence partielle des C60 et de leur distribution à l'intérieur du tube. Les résultats expérimentaux sont supportés par des simulations numériques de la densité d'états et de la conductance des nanotubes de carbone avec des fullerènes fusionnés à l'intérieur (K. Katin, M. Maslov).Les nanofils semiconducteurs (sc-NWs) font l'objet de recherches actives depuis ces dix dernières années. Ils représentent des systèmes modèles pour l’étude des propriété électronique objet quasi-1D. Ils représentent en outre des possibilités de modulation de la structure de bande aussi que de contrôle de la densité de porteurs. Dans ce domaine de recherche, les nanofils semi-conducteurs à base de composes III-V tel que InAs, ont une place particulière en raison de la faible masse effective des porteurs de charge. Nous avons étudié la conductance de nanofils individuels dans une large gamme de champs magnétiques (jusqu'à 60T). Les mesures en champ nul et en champ faible ont démontré un transport faiblement diffusif dans ces nanofils. Les mesures de transport sous champ magnétique intense ont révélé une forte chute de la conductance au dessus d'un champ critique qui s'élève clairement avec l'énergie de Fermi. Cet effet est interprété par la perte de canaux de conduction une fois que toutes les sous-bandes magnéto-électriques, décalés vers les hautes énergies par le champ magnétique, ont traversé l'énergie de Fermi. Les calculs de structure de bande préliminaires (Y-M. Niquet), en prenant en compte les confinements latéraux et magnétiques, sont en bon accord qualitatif avec les résultats observés dans le régime de champ magnétique intense. Ce résultat est la première observation des effets de structure de bande dans les expériences de magnéto-transport sur les sc-NWsThe scope of this thesis is related to the electronic properties of quasi 1D systems probed by high field magnetotransport. Two different systems exhibiting quasi-1D confinement have been considered: carbon C60 peapods (C60@SWCNTs) and InAs semiconductor nanowires. The magnetotransport measurements on single nano-objets have been used to investigate the specific electronic structure of these 1D systems. In both cases, the high magnetic fields experiments have been supported by structural characterisation and conductance measurements at zero field.The encapsulation of various molecules inside carbon nanotubes (CNTs), as for instance C60 fullerenes encapsulated in SWCNT, constitutes promising routes towards the tunability of the CNT conductance. Among the wide variety of filled CNTs, peapods represent a pioneer hybrid structure discovered in 1998. Since that time, their electronic structure has been subjected to intense and controversial theoretical studies together with a limited number of experimental realizations. In this thesis the electronic properties of individual fullerene peapods have been investigated by combining micro-Raman spectroscopy and magnetotransport measurements on the same devices. We bring evidence that the encapsulated C60 strongly modify the electronic band structure of semiconducting nanotubes in the vicinity of the charge neutrality point, including a rigid shift and a partial filling of the energy gap. In addition by playing with a selective UV excitation of the fullerene, we demonstrate that the electronic coupling between the C60 and the CNT is strongly modified by the partial coalescence of the C60 and their distribution inside the tube. The experimental results are supported by numerical simulations of the Density of States and the conductance of CNTs with coalesced fullerenes inside (K. Katin, M. Maslov).Semiconductor nanowires (sc-NWs) are being the subject of intense researches started a decade ago. They represent model systems for the exploration of the electronic properties inerrant to the quasi1-D confinement. Moreover they offer the possibility to play with band structure tailoring and carrier doping. In this direction III-V sc-NWs such as InAs NWs have played a particular role due to the small electron effective mass. We have studied the high magnetic field conductance of single nanowires. Prior to the high field measurements, the zero and low field investigations have demonstrated a weakly diffusive regime of the carrier transport in these wires. The high field investigations have revealed a drastic conductance drop above a critical field, which clearly rises with the Fermi energy. This effect is interpreted by the loss of conducting channels once all the magneto-electric subbands, shifted toward the high energy range by the magnetic field, have crossed the Fermi energy. Preliminary band structure calculations (Y-M. Niquet), taking into account the lateral and magnetic confinements, are in fairly good qualitative agreement with the observed result in the high field regime. This result is the first observation of band structure effects in magneto-transport experiments on sc-NWs
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Farvadi, F., A. M. Tamaddon, and F. Hashemi. "PEG-grafted Hyperbranched Polyethyleneimine-Oxidized Single Walled Carbon Nanotube Complex (PEG-PEI-SWNT) for Sustained Delivery of Doxorubicin." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34928.
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To take advantages of single-walled carbon nanotubes (SWNTs) for cellular delivery of chemotherapeutic
agents (e.g. doxorubicin) in order to decrease doxorubicin toxicity and increase its efficacy, we aimed to
develop a novel approach to aqueous disperse and stabilize SWNTs through consequent steps of oxidation
(oxSWNT) and PEG-PEI complexation (PEG-PEI-SWNT). Doxorubicin was loaded onto the modified
SWNTs in alkalione pH with more considerable capacity ( 900 %) than those previously reported, due to
complex formation with PEI proved by UV-visible spectroscopy. The loaded carrier was stable in physiologic
simulated medium. Drug release was prolonged and dilution independent, but exhibited pH-dependent
burst release that makes SWNTs as suitable in vivo drug carriers in acidic tumor milieu.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34928
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Joseph, Johnson. "Numerical Modeling and Characterization of Vertically Aligned Carbon Nanotube Arrays." UKnowledge, 2013. http://uknowledge.uky.edu/me_etds/28.
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Since their discoveries, carbon nanotubes have been widely studied, but mostly in the forms of 1D individual carbon nanotube (CNT). From practical application point of view, it is highly desirable to produce carbon nanotubes in large scales. This has resulted in a new class of carbon nanotube material, called the vertically aligned carbon nanotube arrays (VA-CNTs). To date, our ability to design and model this complex material is still limited. The classical molecular mechanics methods used to model individual CNTs are not applicable to the modeling of VA-CNT structures due to the significant computational efforts required. This research is to develop efficient structural mechanics approaches to design, model and characterize the mechanical responses of the VA-CNTs. The structural beam and shell mechanics are generally applicable to the well aligned VA-CNTs prepared by template synthesis while the structural solid elements are more applicable to much complex, super-long VA-CNTs from template-free synthesis. VA-CNTs are also highly “tunable” from the structure standpoint. The architectures and geometric parameters of the VA-CNTs have been thoroughly examined, including tube configuration, tube diameter, tube height, nanotube array density, tube distribution pattern, among many other factors. Overall, the structural mechanics approaches are simple and robust methods for design and characterization of these novel carbon nanomaterials
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Motaragheb, Jafarpour Saeed [Verfasser], Stefan E. [Akademischer Betreuer] Schulz, and Thomas [Akademischer Betreuer] Wågberg. "Investigation of multicomponent catalyst systems for type-selective growth of SWCNTs by CVD / Saeed Motaragheb Jafarpour ; Stefan E. Schulz, Thomas Wågberg." Chemnitz : Technische Universität Chemnitz, 2020. http://d-nb.info/1219664340/34.
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Zhang, Xiefei. "Studies on Single Wall Carbon Nanotube and Polymer Composite Films and Fibers." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7610.
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Single wall carbon nanotubes (SWNT) have been extensively studied over the last decade due to their excellent comprehensive properties for a variety of applications. This study is focused on the applications of SWNTs as reinforcement for polymer matrices. Due to van der Waal interactions, SWNTs form bundles of about 30 nm diameters. In order to take full advantage of the SWNT mechanical properties, SWNT must exfoliate or at least disperse in small diameter bundle size. Optical microscopy and SEM only give qualitative information of dispersion. Quantitative characterization through TEM or AFM can be time consuming in order to get statistical result. In this study, simple method is developed to quantitatively estimate the size of SWNT bundle in dispersion based on the geometry controlled electrical percolation behavior. The SWNTs can be dispersed /exfoliated via PVP wrapped SWNT aqueous dispersion assisted by surfactants such as sodium dodycel sulfate. PVA / SWNT composite films prepared through PVP wrapped SWNTs exhibit improved mechanical properties as well as the evidence of load transfer from the polymer matrix to the SWNT as monitored by the Raman spectroscopy. SWNT can also be well dispersed into PVA/DMSO/H2O solution. Gel spinning of PVA/SWNT composite fiber has been successfully carried out with improved mechanical properties. Functionalized tubes can be used to enhance SWNT dispersion and exfoliation. Oxidation in strong acids is one method used for functionalizing nanotubes. SWNTs have been functionalized in nitric acid. The structure and properties of films (buckypaper) processed from nitric acid functionalized tubes have been studied exhibiting high tensile strength and high electrical conductivity. Nitric acid treatment results in selective degradation of the small diameter tubes.
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Xie, Yao. "A Study on Novel Methods to Improve Conductivity of Carbon Nanotube Films." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1418309288.
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Allehyani, Esam. "Synthesis and Characterization of PEO-PS-PEO Triblock Copolymer Conjugated with Ni-NTA for Biosensors." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2018. http://digitalcommons.auctr.edu/cauetds/157.
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Poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) triblock copolymer with di-hydroxyl terminated groups (HO-PEO-PS-PEO-OH) was conjugated with nitrilotriacetic acid (NTA) via esterification reaction using N,N'-Dicyclohexylcarbodiimide (DCC), 4-Dimethylaminopyridine (DMAP) and Dimethylformamide (DMF) as a solvent at 80 ○C. The poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) with NTA end groups (NTA-PEO-PS-PEO-NTA) was characterized and structure confirmed by 1H NMR, 13C NMR, and FT-IR spectroscopies.
Thermogravimetric analysis (TGA) was carried out to investigate the thermal stability of the starting triblock copolymer poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) with di-hydroxyl terminated groups (HO-PEO-PS-PEO-OH) and the conjugated poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) functional polymer (NTA-PEO-PS-PEO-NTA). Surface morphologies of the (HO-PEO-PS-PEO-OH) and (NTA-PEO-PS-PEO-NTA) were studied by atomic force microscopy. In addition, the size distributions were determined using dynamic light scattering. The thermal behavior of the (HO-PEO-PS-PEO-OH) and (NTA-PEO-PS-PEO-NTA) were examined by differential scanning calorimetry (DSC). DSC thermograms indicate the formation of a two phase polymer matrix.
The poly(ethylene oxide)-poly(styrene)-poly(ethylene oxide) with NTA functionalized end groups (NTA-PEO-PS-PEO-NTA) was bound or chelated with Ni(II) metal ion. The binding studies were carried out by ultraviolet-visible (UV-Vis) spectroscopy.
The electronic behaviors of PEO-b-PS-b-PEO/ PS/ NTA-PEO-b-PS-b-PEO-NTA with ratio (1/5/1) and PEO-b-PS-b-PEO/ PS/ NTA-PEO-b-PS-b-PEO-NTA-Ni containing 1% of oxidized single-walled carbon nanotubes (SWCNTs) were investigated by I–V plots from Kelvin sensing. The I–V plots before sensitizing with protein varied from the I–V plots after binding with protein indicating that the composites may be used as active components in biosensors.
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GIULIANI, ANGELA. "Novel carbon nanostructured based materials for energy related catalysis and electrochemical sensing of small biomolecules." Doctoral thesis, Università degli Studi di Trieste, 2017. http://hdl.handle.net/11368/2908177.
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The interest for carbon nanostructure-based hierarchical materials for electrochemical applications has been growing continuously in the last decade, from both an energy and sensing perspective. The use of carbon nanostructures is permitting to explore new opportunities in these research fields. Graphene, carbon nanotubes (CNTs) and single-walled carbon nanohorns (SWCNHs) can contribute to the design of revolutionary devices thanks to their special electronic and structural properties. This dissertation discusses the opportunity of carbon nanostructures integration into the assembly of hierarchical nanomaterials for electrochemical catalysis and electrochemical sensing applications. In particular, the major efforts have been focused in the use of SWCNHs due to their high purity, high conductivity, morphology and porosity, which can considerably aid to enhance performances. The hybrid materials have been synthetized using a hierarchical approach in order to achieve multicomposite-multifunctional nanomaterials able to orchestrate energy related processes such as O2 reduction reaction (ORR) and CO2 reduction reaction (CO2RR) or allow specific H2O2 sensing. In particular, two catalytic systems named t-Fe@MWCNTs (featuring Fe-filled functionalized multi-walled carbon nanotubes) and g-N-SWCNHs (featuring N-doped graphitized carbon nanohorns) have been employed for the O2 reduction reaction catalysis. On the other hand, ternary systems named Pd/TiO2@ox-SWCNHs (integrating oxidized SWCNHs, Pd and TiO2 in a precise hierarchical order) and NiCyclam@BMIM/p-SWCNHs (based on the heterogenization of molecular NiCyclam by embedding into pristine SWCNHs-supported ionic liquids) have been employed for the CO2 reduction catalysis. Finally, a catalyst based on the coating of oxidized SWCNHs with CeO2 (named ox-SWCNHs/CeO2) has been employed for the catalysis of H2O2 reduction exploited for H2O2 amperometric sensing. In all cases, the nanocarbon scaffold may play a multi-role, facilitating electron transfer steps, bringing up specific textural properties, and contributing to physically adsorb gaseous reactants. The result is an enhancement of the catalytic performance in terms of activity, selectivity and stability, which has been communicated through publication (or in the process of being published) in peer-reviewed journals.
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Furuhashi, Toyohisa. "STUDY OF PROPANE ADSORPTION ISOTHERM ON PURIFIED HIPCO SINGLE-WALLED CARBON NANOTUBES." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1967978731&sid=2&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Jirlén, Johan, and Emil Kauppi. "Carbon Nanotube Raman Spectra Calculations using Density Functional Theory." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62169.
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Utilizing density functional theory (DFT) the Vienna Ab initio Simulation Package (VASP) was used to calculate the Raman spectra for five single-walled carbon nanotubes (SWCNTs) with chiralities (4,4), (6,6), (8,0), (12,0) and (7,1). The radial breathing mode (RBM), when compared with experimental frequencies, shows good correlation. When compared to RBM:s calculated with tight binding the frequencies calculated with DFT displayed higher accuracy. The precision of G-band frequencies were inconclusive due to lack of experimental data. The frequencies did not agree well with the results from tight-binding theory. The correctness of the Raman activity estimations using results from DFT calculations was found to be questionable. An unknown mode, which was found to be highly Raman active in the calculated spectra of (4,4), (6,6), and possibly (8,0), and (12,0), is also discussed. It was concluded that further calculations on larger tubes, especially armchair tubes are relevant for future studies. Further verification of the determination of Raman activity is also needed.Supervisors: Daniel Hedman, Andreas Larsson and Sven Öberg
F7042T - Project in Engineering Physics
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Sousa, Marcos Antonio Moura de. "Modelos de circuitos equivalentes para explicar espectros de impedância de dispositivos de efeito de campo." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-19062013-080945/.
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Biossensores que empregam dispositivos de efeitos de campo podem ser obtidos em diversas arquiteturas, incluindo dispositivos Eletrólito-Isolante-Semicondutor (EIS), que são capacitores em que o eletrodo metálico é substituído por um filme e uma solução. Medindo-se a capacitância em função do potencial aplicado, é possível detectar variações de pH oriundas de reações ou interações entre o filme e o analito. Nesta dissertação, sensores foram produzidos com a adsorção de filmes automontados de dendrímero (PAMAM) e nanotubos de carbono (SWNT) num chip. Medidas de espectroscopia de impedância foram realizadas para investigar o crescimento de cada bicamada do filme automontado, e os dados foram analisados com circuitos equivalentes que continham uma capacitância de dupla camada, um elemento de fase constante e uma capacitância para a região de depleção. Para o chip, os melhores ajustes foram obtidos na frequência de 2 kHz, em que a concentração de dopantes foi 6,6x1020 m-3 para o chip com isolante de SiO2 e de 1,1x1021 m-3 para o chip com isolante de SiO2/Ta2O5. O potencial de banda plana foi -0,2 V e -0,06V, respectivamente. Para os chips recobertos com os filmes de PAMAM/SWNT, observamos que a região de depleção é causada pelas cargas positivas do PAMAM. Com relação às implicações para biossensores, verificamos que o desempenho ótimo deve ser obtido com 3 bicamadas de PAMAM/SWNT. Isso pode explicar a observação empírica na literatura de que existe uma espessura ideal dos filmes para um desempenho otimizado.Biosensors based on field effect devices can be produced with several architectures, including Electrolyte-Insulator-Semiconductor (EIS) devices, which are capacitors where conventional metal electrodes are replaced by a sensing layer and an electrolyte solution. By measuring the capacitance as a function of the bias voltage, it is possible to detect pH changes that may originate from reactions or interactions between the film in the sensing unit and the analyte. In this study sensors were obtained by adsorbing layer-by-layer (LbL) films made with dendrimers (PAMAM) and carbon nanotubes (SWNT) on a semiconductor chip. Impedance spectroscopy measurements were performed to monitor the growth of each bilayer in the LbL film, whose data were analyzed with equivalent circuits containing a double-layer capacitance, a constant phase element and a capacitance for the depletion region. The results for the semiconductor chip could be best fitted for a frequency of 2 kHz, where the doping concentration was 6.6 x1020 m-3 for the insulating SiO2 layer and 1.1 x1021 m-3 for the SiO2/Ta2O5 layer. The flat band voltage was -0.2 V and -0.06 V, respectively. In the analysis of the chip coated with different numbers of PAMAM/SWNT bilayers, we found that the depletion region appears as a contribution from the positive charges in the PAMAM layer. With regard to implications for biosensors, we found that optimized performance should be reached with three PAMAM/SWNT bilayers, which may explain the empirical finding in the literature that an ideal thickness exists for enhanced performance.
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Lima, Leandro Holanda Fernandes de. "Síntese e caracterização de compósitos de nanotubos de carbono e nanopartículas de prata e sua aplicação como substrato SERS." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-22102013-102146/.
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Neste trabalho foram produzidos compósitos de nanotubos de carbono contendo nanopartículas de prata, os quais foram testados como substratos SERS (Surface-enhanced Raman Spectroscopy) na detecção do cristal violeta. Para obter tais compósitos foram necessárias modificações de nanotubos de carbono através de funcionalizações químicas para inserção de grupos carboxila e tiol, capazes de interferir no crescimento de nanopartículas metálicas através de um processo de redução térmica do acetato de prata sobre a superfície das amostras de nanotubo. Para a preparação de tais compósitos foram utilizadas duas amostras de nanotubos, uma de parede simples (SWNT) e outra de paredes múltiplas (MWNT) a fim de avaliar diferenças nos tamanhos e homogeneidade das nanopartículas formadas. Utilizou-se como ferramenta investigativa a espectroscopia Raman na caracterização destes compósitos, que forneceu informações sobre interação dos nanotubos de carbono com as nanopartículas de prata e mudanças estruturais ocasionadas durante a gama de funcionalizações. Para avaliar a morfologia dos compósitos foi utilizada a microscopia eletrônica de varredura (MEV) e a microscopia eletrônica de transmissão (TEM) que forneceram informações sobre o tamanho e a disposição das nanopartículas formadas através do tratamento térmico dos nanotubos com acetato de prata. Os compósitos preparados foram aplicados como substrato SERS na detecção do cristal violeta. Nesta aplicação foi avaliada a capacidade dos nanotubos em adsorver estas moléculas e o potencial do substrato na intensificação do espectro Raman do analito. Observou-se que a adsorção do cristal violeta sobre uma amostra de SWNT foi máxima após o tempo de 60 minutos de agitação. Já o substrato utilizado (SWNT-COOH@Ag) permitiu a detecção do cristal violeta em solução aquosa com concentração de até 1,0.10-8 mol.L-1. Utilizando o mapeamento Raman foi possível avaliar a presença do analito através do monitoramento de uma banda do espectro vibracional do analito intensificada pelo efeito SERSIn this work, we produced carbon nanotube composites containing silver nanoparticles, which were tested as SERS (Surface-enhanced Raman Spectroscopy) substrates in the detection of crystal violet. For these the synthesis of these composites modifications of the carbon nanotubes surface through chemical functionalizations were necessary for insertion of carboxyl and thiol groups, that can affect the growth of metal nanoparticles in thermal reduction process of silver acetate on the surface of the nanotube samples. For the preparation of such composites have single walled carbon nanotubes (SWNT) and a multi-walled carbon nanotubes (MWNT) to evaluate differences in size and homogeneity of the nanoparticles formed. Raman spectroscopy was used as an investigative tool in the characterization of these composites, which provided information on the interaction of carbon nanotubes with silver nanoparticles and structural changes ocurring during the range of functionalizations. To evaluate the morphology of the composites scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used. These techniques provided information about the size and assembly of the silver nanoparticles formed by heat treatment of the nanotubes with silver acetate. The nanotubes@Ag composites were applied as SERS substrates in the detection of crystal violet. In this application, we evaluated the ability of nanotubes to adsorb these molecules and the substrate potential in enhancing the Raman spectrum of the analyte. It was observed that the adsorption of the crystal violet on a sample of SWNT was maximal after 60 minutes of stirring. Substrate used (SWNT-COOH @ Ag) allowed detection of crystal violet in aqueous solution with a concentration as low as 1,0.10-8 mol.L-1. Using Raman mapping was possible to evaluate the presence of the analyte by monitoring a band of vibrational spectrum of the analyte enhanced by SERS effect.
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Al, Mafarage Ali M. "Processing and Properties of Multifunctional Two-Dimensional Nanocomposite Based on Single Wall Carbon Nanotubes." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1556310855748631.
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Marques, Rita Ruivo Neves. "Development of hybrid TiO2/SWCNT photocatalysts." Master's thesis, 2009. http://hdl.handle.net/10216/66796.
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